Perforation of the small intestine in a non reducible spigelian herna, by a foreign body

Summary

An 87yo man was referred for abdominal pain over a pre-existing hernia in the right iliac fossa. Physical examination revealed a red painful palpable mass in the right lower abdominal quadrant. Abdominal CT scan revealed a loop of small intestine trapped into the abdominal wall. The patient underwent emergency laparotomy and the intraoperative findings consisted of a spigelian hernia, with perforation of the contained small intestine by a chicken bone (clavicle). The intestinal perforation was sutured and a polypropylene mesh plug and patch repair of the hernia was executed. The patient had an uneventful recovery and was discharged in stable condition. Our patient had a rare type of hernia with a rare complication. The arrow-shaped chicken bone led to irreducibility of the hernia and eventually to intestinal perforation. The diagnosis of spigelian hernias by history and physical examination is notoriously difficult. Recently, imaging modalities have increased preoperative diagnostic yield.

Key words:
spigelian hernia, small intestine perforation, foreign body ingestion.

Introduction

Ingestion of foreign bodies usually is accidental or, in the case of mentally diseased persons, a voluntary action. Most often these bodies follow the natural course of the gastrointestinal tract until they are naturally expelled from the body. Occasionally they become responsible for the development of complications especially when other conditions affect the gastrointestinal tract. We report the case of a chicken bone entrapped in a Spigelian hernia which thus became irreducible and eventually led the patient to the operating theatre.

Case Report

An 87 year-old man hospitalized for a urinary tract infection was referred to our department due to a irreducible a spigelian hernia on the right abdominal wall. The hernia was detected by the admitting physician 4 days ago, but at that time was easily reduced and was not considered a priority. The patient’s medical history included glaucoma, essential hypertension and benign hypertrophy of the prostate gland.

Physical examination revealed a painful, compressible, but not reducible lump with ill defined borders, cephalad and medial of the right inguinal ligament. The patient was afebrile and presented a mild leukocytosis (WBC 12.600/ml) and polymorphonucleosis (82% on smear deferential) which could derive from the urinary tract infection. His blood biochemistry and abdominal X-ray were normal. Abdominal CT depicted a hernia of the right lateral abdominal wall with blurring of the adjacent tissues (Figure 1). The patient was promptly taken to the operation theatre. 

By incising the skin obliquely over the mass and dividing the aponeurosis of the external oblique muscle along the direction of its fibers we revealed the hernia sac which still could not be reduced in the abdominal cavity. Opening the sac liberated a loop of small bowel herniating through a 2 cm orifice on the Spigelian line. A localized area of the bowel wall presented moderate ischemic changes and a tiny area of necrosis.  On palpation we felt a “triangular” foreign body, approximately 4 cm in length, entrapped in the bowel loop. By opening a hole on the necrotic area we pulled the foreign body – a chicken clavicle (Figure 2) - out of the intestine. Obviously the bone was able to advance through the hernia orifice together with the herniated intestine by approximation of its two legs. Then, once through the orifice, the bone recovered its natural shape with its legs wide apart so a retrograde movement became impossible. On the same time due to its size it could not follow the bowel loop curve and be propulsed forward. Consequently it became trapped in the bowel and rendered the hernia non reducible. After the extraction of the chicken bone we sutured the hole, returned the bowel in the abdomen and ligated the sac on its neck. We sealed the hernia orifice with a prolene plug secured in place with non absorbable sutures. Then we covered the internal oblique and the front petal of the rectus abdominis muscle with a 6 X 4 cm on-lay prolene mesh and closed the abdominal wall. The patient’s postoperative course was uneventful and he was discharged 5 days later after resuming complete oral alimentation. He was in perfect condition in his monthly follow-up examination and has been placed on a regular follow up program.

Discussion

The semilunar line, also known as Spigelian line, was described by Adrian van der Spieghel and represents the transition line of transversus abdominis muscle to the aponeurosis that will eventually become part of the rectus abdominis sheath (1). This aponeurosis extends from the semilunar line up to the rectus abdominis and is also called Spigelian. Spigelian hernia, firstly described by Klinkosch in 1764 (2), is any hernia protruding through this aponeurosis. Usually they lie in the so-called Spigelian zone, a 6cm-width transverse zone cephalad to the interspinal plane and most often at the junction of Spighelian aponeurosis with the semicircular line of Douglass (3). The various theories proposed for the etiology of herniation through the Spigelian aponeurosis have been recently reviewed (4). Except trauma or congenital etiology the most plausible theory seems to be the existence of musculoaponeurotic defects.

The hernia sac consists of peritoneum, pre-peritoneal fat, occasionally of remnant bands from the transversalis fascia and protrudes towards the aponeurosis of internal oblique. This layer may or may not rupture but the overlying aponeurosis of external oblique is always too strong to be penetrated, so the hernia obtains a T-, or mushroom shape remaining intercalated in the loose space between the layers of the abdominal wall. Accordingly the terms interparietal or interstitial can also correctly be applied. Most often the sac contains omentum or small bowel although reports of colon, gastric, testicular, or ovarian herniation also exist (1, 5).  Because the hernia neck is rigid and narrow, (less than 2 cm in diameter) Spigelian hernias are prone to irreducibility and strangulation (4) therefore they are better repaired on diagnosis (1, 6, 7).

The true incidence of Spigelian hernias remains unknown. Approximately 1000 cases were reported until 1992 (8). Nowadays they are often incidentally discovered during laparoscopy performed for different reasons (9). Still they comprise approximately 2% of the total abdominal walls hernias (9). They can be met on both sides and present a slight preponderance for female sex (4). Clinical diagnosis remains difficult unless the suspicion is high. They usually present as an intermittent ill defined mass laterally to rectus abdominis (3,6) and remain asymptomatic unless complications develop. Frequently they are combined with pain or numbness of the overlying area (3, 6). Differential diagnosis includes rectus sheath hematoma, abdominal wall abscess, as well as fibroma, lipoma, sarcoma, hemangioma or seroma. U/S or CT imaging contributes substantially in setting the diagnosis and both can depict the hernia orifice in Spigelian aponeurosis with the same sensitivity (6, 10). 

Because of the high risk of complications early surgical repair is indicated. This can be either open or laparoscopic with none being superior to the other. However the laparoscopic approach seems to be followed by less morbidity and shorter hospitalization (3, 5, 6, and 7). On the other hand complicated hernias are better dealt with open surgery. As far as reconstruction is concerned, simple suture closure of the defect is adequate in most cases; but when the aponeurosis has multiple defects or is weak, or when the orifice is large the use of prosthetic material seems justified(11, 12).

Perforation of a herniating small bowel due to a chicken bone is infrequent in literature and we could only retrieve two cases from literature (13, 14). The setting may be underreported with most cases being considered preoperatively as strangulated hernias. Chicken bones are hardly visible in simple X-ray films and as our case implies may be missed even by CT. Because of the combined difficulty in diagnosing clinically a Spigelian hernia and in depicting correctly the reason of perforation we believe that our case is highly unusual and we report it as such.

Conflict of Interest Statement

No conflicts declared.

Corresponding Author:

Iraklis Delikonstantinou

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